In the recent decade diastolic dysfunction has been extensively studied. It has been found that the clinical syndrome of heart failure may result from two entirely different disorders--systolic and diastolic impairment or both. Available evidence indicates that the left ventricular filling pattern is altered with progressing diastolic dysfunction. Left ventricular diastolic dysfunction is a sensitive marker of myocardial damage and it can be used to monitor a spectrum of changes ranging from impaired relaxation through pseudo-normalization to restrictive filling pattern. The restrictive filling pattern, irrespective of its etiology, has a negative effect on prognosis, especially when it coincides with reduced left ventricular ejection fraction. Patients with systolic heart failure and restrictive filling pattern show a lower exercise tolerance than their counterparts with non-restrictive filling. This indicates a significant role of diastolic dysfunction in the development of clinical symptoms in patients with left ventricular systolic impairment. Progress in the understanding of diastolic dysfunction may allow for better evaluation of prognosis and therapeutic efficacy and for monitoring of patients with systolic dysfunction.